LMC6464AMJ-QML datasheet(14/18 Pages) NSC

14 / 18 page

Typical Single-Supply Applications

TRANSDUCER INTERFACE CIRCUITS

Photocells can be used in portable light measuring instru-

ments. The LMC6462, which can be operated off a battery, is

an excellent choice for this circuit because of its very low in-

put current and offset voltage.

LMC6462 AS A COMPARATOR

Figure 17 shows the application of the LMC6462 as a com-

parator. The hysteresis is determined by the ratio of the two

resistors. The LMC6462 can thus be used as a micropower

comparator, in applications where the quiescent current is an

important parameter.

HALF-WAVE AND FULL-WAVE RECTIFIERS

Figure 18 Figure 19,R

I limits current into the amplifier

since excess current can be caused by the input voltage ex-

ceeding the supply voltage.

PRECISION CURRENT SOURCE

The output current I

OUT is given by:

OSCILLATORS

For single supply 5V operation, the output of the circuit will

swing from 0V to 5V. The voltage divider set up R

2,R3 and

4 will cause the non-inverting input of the LMC6462 to

move from 1.67V (1⁄3 of 5V) to 3.33V (2⁄3 of 5V). This voltage

behaves as the threshold voltage.

1 and C1 determine the time constant of the circuit. The fre-

quency of oscillation, f

OSC is

DS012051-22

FIGURE 16. Photo Detector Circuit

DS012051-23

FIGURE 17. Comparator with Hysteresis

DS012051-24

FIGURE 18. Half-Wave Rectifier with

Input Current Protection (R

DS012051-25

FIGURE 19. Full-Wave Rectifier

with Input Current Protection (R

DS012051-26

FIGURE 20. Precision Current Source

DS012051-27

FIGURE 21. 1 Hz Square-Wave Oscillator

LMC6464AMJ-QML Datasheet(PDF) 14 Page - National Semiconductor (TI)

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